How does the bend tool work?
The Bend Tool rotates around the 3D cursor and bends the selected parts of a mesh toward the mouse cursor position.

The tool is explained in this video.

Start position (white cross indicates position of mouse cursor)



End position and effect:



For predictable results use the bend tool in the orthographic modes.

Start position with 3D cursor at center:



Similar result:



Related:


Which tool allows bending a mesh?